Service-Oriented Modeling and Architecture at IBM

The SOMA method was developed as an engagement model within IBM's Global Business Services group, and while public papers and descriptions were available it was primarily a method used by consultants in the field and not available to IBM customers. On the other hand the RUP is a commercial product offering from IBM which customers use to develop their own software development processes. This integrated method offering, RUP/SOMA has been developed to bring the unique aspects of SOMA to the RUP commercial method and make these available to commercial customers.

In the area of SOA Solution design it is not unsurprising to find that many similar elements appeared in these two methods, primarily the following three topic areas.

The Integrated SOA Method

In bringing together the RUP SOA content and SOMA we have brought together the methods, techniques and work products according to the framework below. As you can see the core activities remain the same, the work products remain the same (at this high-level of detail) and we describe here the primary influences that guide the different activities (although most activities take into account some aspect of most of these influences). Note also that this remains an iterative method, that the identification, specification and realization activities often happen in multiple, and often overlapping, iterations focused on different services or services in different domains.

The current method does not cover the deployment, provisioning and management of services at this time.

Phase: Identification

As we have said, the core approach to service identification is common to both SOMA and RUP, however some differences existed and some of these differences are surfaced in the resulting integrated method. The following table describes how the techniques from SOMA are realized in the integrated RUP/SOMA and where in the resulting method content the topics can be found. Where possible names have been preserved from SOMA except where existing RUP material had a stronger precedence.

This results in a Phase structure for Identification which looks like this:

Also the RUP method content includes the following elements that had no corresponding technique in SOMA.

• Task: Data Model Analysis- identification of candidate services from data models.
• Task: Business Rule Analysis- identification of candidate services from business rules.
• Guideline: Service Data Encapsulation - the discussion of data management issues in service design.

Phase: Specification

Service Specification has been developed in a similar fashion to Identification, and described in the table below.

This results in a Phase structure for Specification which looks like this:

Also the RUP method content includes the following elements that had no corresponding technique in SOMA.

• Concept: Service Portfolio- the discussion of issues surrounding the management and use of an enterprise-wide service portfolio.
• Concept: Solution Partitioning- the use of Artifact: Service Partition to model elements to manage and categorize services in a solution model and/or service portfolio.
• Guideline: Service Mediation  - a discussion of mediation as a key concept in service design, and the modeling of different mediation forms in the Artifact: Service Model.

Phase: Realization

Service Realization has been developed in a similar fashion to the two activities above, and described in the table below.

This results in a Phase structure for realization which looks like this:

The Service Model

In SOMA the Service Model is described using the picture below; it is a single, document based, work product that encompasses the different technical and lifecycle views of the services identified and specified during a project. The different sections of the service model are listed in more detail in the Artifact: Service Model in RUP/SOMA.

The RUP Artifact: Service Model is described in both a document form and a UML form (Template: Service Model in Word and Template: Service Model in UML) though it is more likely that a project will use elements of both of these forms in presenting the results of their work.